Rotary Steam Engines: Page 4

Updated: 5 Sept 2022

More on Inman engine added (1873)
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Hendey engine: 1870
Left: The Hendey rotary engine: 1870

This engine was built by Henry J. Hendey to power his first factory. After that he seems to have devoted himself to making machine tools such as lathes, planers, and shapers.

The internals of the engne are a matter for speculation. Not for the first time, we note that the governing arrangements take up as much or more space than the actual engine.

Googling 'Hendey rotary engine' comes up with nothing except this picture.


Race engine: 1871
Left: The Race rotary engine: 1871

This engine was patented by Washburn Race of Lockport, New York. Race was his surname and there is no suggestion that this engine was intended for any form of racing.

In Fig 1, D is the steam inlet pipe. C is a hollow shaft through which the steam exhausts.

From US Patent 116,352 granted 27 June 1871

The engine uses two swinging abutments h and h' that double as inlet valves, but this time they are constrained in the hope of making them move smoothly, rather than just banging about in the cylinder. The valves open because of the steam pressure behind them; the speed of opening is controlled by the incline i attached to the rotor. (Top left of Fig 2) The inlet valves are closed again by the ramp S, also attached to the rotor. Steam exhaust is through the duct k into the hollow central shaft.

Apart from his patent, Washburn Race is unknown to Google, so it is fair to conclude that this engine did not thrive.


Stocker Rotary Engine: 1872
Left: The Stocker Rotary Engine: 1872

"The sector pistons are each connected through central concentric shafts to slotted cranks in which a sliding box and link connect to a crank on a shaft eccentric to the sector shaft. A differential movement of the sectors is produced while rotating which rotates the driven shaft by the outside slotted crank connections."

An example of the "pursuing pistons" approach to rotary engine design. Reuleaux says, that as a consequence of the large area between the outer surface of the pistons and the inside of the cylinder, "The joint between piston and chamber can without difficulty be made steam-tight,..."

From "Mechanical Movements, Devices and Appliances" Hiscox, 1899


Faucett Rotary Engine: 1872
Left: The Faucett Rotary Engine: 1872

This is another eccentric-cylinder rotary engine relying on a line seal to remain steam-tight. Two such cylinders were arranged at 180 degrees to give a smoother output torque.

The steam inlet and exhaust passages could be swopped over by the valve G so the engine was reversible.

From US patent 122,713 granted Jan 1872


Shaw & Baker Rotary Engine: 1872
Left: The Shaw & Baker engine: 1873

This engine was patented by Levi M Shaw And Allen S Baker of Evansville, Wisconsin. It is not really a rotary engine so much as a "disc engine".

The output shaft is F. The patent text claims that the output torque is constant.

From US patent 143,723 granted Oct 1873

Shaw & Baker Rotary Engine: 1872
Left: The Shaw & Baker engine: 1873

Here we learn that the Shaw & Baker engine was abandoned due to its poor efficiency, the fate of most rotary engines.

From A Field Guide to American Windmills by T Lindsay Baker. University of Oklahoma Press, 1 Jan 1985

The Baker company still exists, making water-supply products. Here are a few more details from on the rotary engine from The Baker Monitor.

"It all began in 1872 with the designing of a rotary steam engine by Allen S. Baker and Levi Shaw. Mr. Baker took the design to a Milwaukee firm to be built and the tests looked promising. In April of 1873, Caleb Snashall and L. M. Mygatt from the hardware store and Almeron Eager and W. S. Smith from the general store, proposed to Baker and Shaw that the six of them each subscribe $1,000 to organize a company to build rotary steam engines and also run a machine shop repair business. Some stories say that Mr. Eager and Mr. Baker formulated the idea while going for a buggy ride and having a picnic together at Liberty Pole Hill. In any case, the organization was formed and the following officers elected: President, Caleb Snashall; Treasurer, Almeron Eager; Secretary, W. S.Smith. Allen Baker was made Foreman and General Superintendent. The company was named the A. S. Baker Company. These six were very enterprising men but very different from each other in their talents and aspirations. Some were primarily interested in making money and some just loved to build things; but all had a great love for Evansville and wanted to see the city grow and thrive."

"Machinery was ordered and a two story frame building was erected at what is now the corner of Enterprise and Church Streets. The "Shop" was opened for business in July of 1873. They made two or three rotary steam engines but soon discontinued them because they proved uneconomical to operate. The only other activity carried on during that summer was the repair of reapers and mowers."


Hardy Rotary Engine patent model: 1873
Left: Patent model of the Hardy Rotary Engine of 1873

This engine was put forward by Dexter D Hardy of Delavan, Illinois.

The patent model shown here is made of wood; it is not clear if it could be disassembled to reveal the inner workings, but if not it would appear to be of little use.

Hardy Rotary Engine patent drawing: 1873
Left: The Hardy Rotary Engine of 1873

We have met Dexter D Hardy before, in 1859 and 1868, patenting engnes that were quite different in principle from each other. His next attempt is completely different again.

The patent text is obscure even by the usual standards of rotary engine patents. Steam enters through an axial bore in the central shaft and passes through the ports g. There are two pairs of pistons labelled I joined together by rigid rods. These move in and out, and are eccentrically mounted on the output shaft, which is in some way caused to rotate.

From US patent 141,436 of Aug 1873


Inman Rotary Engine: 1873
Left: The Inman Rotary Engine: 1873

This rather complicated engine, invented by Mr Charles Inman of Michigan, is based on two sliding vanes on a central cylinder I. It relied on two face-cams on the end of the engine towards us. The inner track in the cam moved the rocking-arm Y which operated inlet valves on each side of the engine, and the outer track controlled the movements of the two vanes.

Apart from a Scientific American article, this engine is unknown to Google, and (not surprisingly) failed to thrive. There is no mention of a patent in the article.

Source: Scientific American 7 June 1873, p358

Inman Rotary Engine: 1873 Inman Rotary Engine: 1873 Inman Rotary Engine: 1873
Left: The Inman Rotary Engine: 1873

First part of the description of the operation of the Inman engine.

Source: Scientific American 7 June 1873, p358

Inman Rotary Engine: 1873 Inman Rotary Engine: 1873 Inman Rotary Engine: 1873
Left: The Inman Rotary Engine: 1873

Second part of the description of the operation of the Inman engine.

Source: Scientific American 7 June 1873, p358


Moss Rotary Engine: 1875
Left: The Moss Rotary Engine: 1875

This engine comes from Dublin, Ireland. The inventor claims that it is the first single-cylinder rotary engine with no dead-point, ie no dead-centre position where it will not move when steam is applied. This seems highly unlikely.

Secondly he appears to claim that constant torque is obtained whether the engine is run expansively or not; this seems doubtful but his explanation of the steam flow is too obscure for any judgment to be made.

There is no menton of a patent, which is unusual. Charles E Moss and his engine are unknown to Google.

Thanks to Paul Burke for drawing this engine to my attention.

From English Mechanic and World of Science 1875


The four rotary steam engines below were illustrated in the US journal "Manufacturer & Builder" for June 1880. Extracts from the contemporary description are in green text. The seals and packings- usually the Achilles Seal of these machines- is highlighted in red or pink, where feasible.

The Pillner-Hill rotary steam engine .
Left: The Pillner-Hill rotary steam engine; cross-section. An English design of the "gear-pump" type.

"The Pillner-Hill has two cylindrical overlapping chambers, and two systems of rotary pistons, which may be compared to cogwheels. These wheels, by the close contact of their cogs, prevent the passage of steam between them, and they are adapted steam-tight to the interior of their cylinders by metallic packing in the tips of their teeth."

The Pappenheim pump appears again. This design appears to be reversible; by rotating the plug cock on the right steam can enter on either side of the rotors. There seems no possibility of expansive use of steam; it probably worked but it would have been dreadfully inefficient. The design is related to the gear-type oil pumps widely used in car engines. This was the type of engine built by Murdoch.

Anonymous rotary steam engine
Left: An anonymous design, (though it looks very much like the Birdsall Holly engine) again of the "gear-pump" type.

Once more the exhaust "eduction" pipe is no bigger than the inlet. The expansive use of steam looks to be impossible. Engines like this are inherently reversible, given suitable steam connections.
The design is similiar to the Roots blower widely used as a supercharger for IC engines.

Anonymous rotary steam engine
Left: Another anonymous design reminiscent of the Shorrocks blower, which was once much used for supercharging IC engines.

"...has four distinct pistons, which slip in and out in the eccentric hub."

At first this looks unworkable as the steam volume expands and then contracts again before the exhaust port is reached allowing no work to be done. However the pipe at the left may not be the exhaust, but an alternative steam inlet for reversing, and there is probably an exhaust port at the bottom, not shown in this contemporary drawing.
The twiddly bit on the right appears to be just a steam admission valve.

Anonymous rotary steam engine
Left: A anonymous rotary design that typifies a common approach to the problem; hinged "abutments" that swivel out of the way as the three "pistons" on the rotor go past.

"The engine has three pistons, two abutments, and two induction and eduction ports."

Here there is at least the possibility of expansive use of steam. However, note that the exhaust "eduction" pipe is no bigger than the inlet. This looks suspicious, but might just be bad drawing.
Rotary steam engine designers were very fond of "abutments" that swung out of the way (or were knocked out of the way) at convenient times, though they inevitably made the engine inherently non-reversible, like this effort here. Given that it has three pistons and two abutments, this might be the Cartwright engine of 1797.

See also the Knowles rotary engine, which has its own page. Its exact date is unknown but appears to be around 1880.

The story of the Rotary Steam Engine continues on Page 5 of this gallery.

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